Location: Columbia Plateau Conservation Research Center
Project Number: 2074-11120-005-002-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 15, 2021
End Date: Sep 14, 2026
Objective:
Conduct research and develop approaches to increase soil carbon or improve related soil properties (e.g., soil health; functional optimization of the soil microbiome) that are marked by increased dryland production, while at the same time lowering inputs and improving resilience to weather-related and climate-driven stressors. Specifically, 1) carry out a comprehensive assessment of the soils and crops in the Pendleton long term experiments (LTEs), and 2) assess how changes in soil C stocks and soil health indicators in the different LTEs affect dryland grain yields and quality, plant disease incidence, soil microbiology, and weed pressure, and to 3) quantify C sequestration in dryland agricultural systems, with emphasis on how N fertilizer and weed control (tillage vs no-till) factor into the carbon balance of a farming operation, within and beyond the farm gate.
Approach:
Objective 1 will be evaluated at the co-located ARS and Oregon State University (OSU) research station near Pendleton, Oregon. This will involve a detailed assessment of the soils and crops every five years in LTEs. Soil samples will be obtained at several depth increments down to rooting depth, with fine-scale samplings (>5cm) near the soil surface in selected treatments. We plan to quantify a variety of organic and mineral C stocks and soil health parameters, including soil carbon and nitrogen, plant tissue C, N, Zn, B, Cl, soil acidification, electrical conductivity, soil enzyme activities, microbial community structure, and bulk density. In addition, soil samples will be scanned in the mid infrared in order to examine changes in the molecular structure of soil organic matter. The mid-infrared spectral data will also be used to develop calibrations for bulk soil C, soil C fractions, and soil health parameters, which will facilitate the high throughput analysis of a large number of samples. The soil analyses will help determine how different tillage intensities, crop rotations, fallow frequency, and residue management practices affect C cycling, C redistribution within the soil profile, and soil health.
Objective 2 will assess how changes in soil C stocks and soil health indicators in the different long-term experiments at Pendleton affect dryland grain yields and quality, plant disease incidence, and weed pressure. We will investigate interactions between the soil microbial activity, crop yields, and soil carbon to determine the role of microbial processes in crop and soil health to develop dryland agricultural systems that reduce soil carbon loss. Crop and weed biomass, and weed cover will be recorded every year at crop maturity in the tillage and fertilizer treatments of the different experiments. Wheat grain yields, as well as grain protein concentration, test weight, and nutritional parameters will also be analyzed at harvest. Plant pathogens will be assessed visually in the field, and lab bioassays will be carried out to test LTE soil for disease suppression and soil borne disease incidence.
Objective 3 will quantify C sequestration in dryland agricultural systems, with emphasis on how tillage, residue management, fallow periods, N fertilizer and weed control (tillage vs no-till) factor into the carbon balance of a farming operation, withi and beyond the farm gate. Using available data from the LTEs and in collaboration with the new objective 4 of the NP 212 project, we will conduct life cycle calculations for full accounting of upstream atmospheric CO2 inputs including those from industrial processes, transportation, as well as C-saving practices within the farm including savings from fertilizer, herbicide, and fuel. The data will be used to inform growers about how different farming practices affect their C footprint and improve soil health. This work will establish the potential for C conservation practices to be adopted weighing expected economic income vs. risk.
